Optimizing the Technique for Invasive Fractional Flow Reserve to Assess Lesion-Specific Ischemia

Brian M. Renard, William Beaumont Hospital
Elvis Cami, William Beaumont Hospital
Monica R. Jiddou-Patros, William Beaumont Hospital
Ahmad Said, William Beaumont Hospital
Herman Kado, William Beaumont Hospital
Justin Trivax, William Beaumont Hospital
Aaron Berman, William Beaumont Hospital
Akhil Gulati, William Beaumont Hospital
Maher Rabah, William Beaumont Hospital
Steven Timmis, William Beaumont Hospital
Mazen Shoukfeh, William Beaumont Hospital
Amr E. Abbas, William Beaumont Hospital
George Hanzel, William Beaumont Hospital
Ivan Hanson, William Beaumont Hospital
Simon Dixon, William Beaumont Hospital
Robert D. Safian, William Beaumont Hospital


© 2019 Lippincott Williams and Wilkins. All rights reserved. Background: Invasive fractional flow reserve (FFRINV) is the standard technique for assessing myocardial ischemia. Pressure distortions and measurement location may influence FFRINV interpretation. We report a technique for performing invasive fractional flow reserve (FFRINV) by minimizing pressure distortions and identifying the proper location to measure FFRINV. Methods: FFRINV recordings were obtained prospectively during manual hyperemic pullback in 100 normal and diseased coronary arteries with single stenosis, using 4 measurements from the terminal vessel, distal-to-the-lesion, proximal vessel, and guiding catheter. FFRINV profiles were developed by plotting FFRINV values (y-axis) and site of measurement (x-axis), stratified by stenosis severity. FFRINV≤0.8 was considered positive for lesion-specific ischemia. Results: Erroneous FFRINV values were observed in 10% of vessels because of aortic pressure distortion and in 21% because of distal pressure drift; these were corrected by disengagement of the guiding catheter and re-equalization of distal pressure/aortic pressure, respectively. There were significant declines in FFRINV from the proximal to the terminal vessel in normal and stenotic coronary arteries (P<0.001). The rate of positive FFRINV was 41% when measured from the terminal vessel and 20% when measured distal-to-the-lesion (P<0.001); 41.5% of positive terminal measurements were reclassified to negative when measured distal-to-the-lesion. Measuring FFRINV 20 to 30 mm distal-to-the-lesion (rather than from the terminal vessel) can reduce errors in measurement and optimize the assessment of lesion-specific ischemia. Conclusions: Meticulous technique (disengagement of the guiding catheter, FFRINV pullback) is required to avoid erroneous FFRINV, which occur in 31% of vessels. Even with optimal technique, FFRINV values are influenced by stenosis severity and the site of pressure measurement. FFRINV values from the terminal vessel may overestimate lesion-specific ischemia, leading to unnecessary revascularization.